variable.c:777
st_table*
rb_generic_ivar_table(obj)
    VALUE obj;
{
    st_table *tbl;

    if (!FL_TEST(obj, FL_EXIVAR)) return 0;
    if (!generic_iv_tbl) return 0;
    if (!st_lookup(generic_iv_tbl, obj, (st_data_t *)&tbl)) return 0;
    return tbl;
}
